Genesis

NSSDCA/COSPAR ID: 2001-034A

Description

The parachute on the Genesis sample return capsule failed to deploy on re-entry. The capsule crashed in the Utah desert. The fragments from the sample return container have been packaged for shipment to Johnson Space Center's curation facility in early October. Scientists are optimistic that they will be able to salvage useful data from the samples.

The primary objective of the Genesis mission is to collect samples of solar wind particles and return them to Earth for detailed analysis. The science objectives are to obtain precise measurements of solar isotopic and elemental abundances and provide a reservoir of solar matter for future scientific analysis. Specifically, the primary scientific objectives were to obtain precise measurements of isotope ratios of oxygen, nitrogen, and solar wind isotopic fractionation. Study of these samples will allow testing of theories of solar system formation and evolution and early nebular composition. A total sample mass of roughly 10 to 20 micrograms is expected.

Spacecraft and Subsystems

The Genesis spacecraft has a launch mass of 636 kg, including 142 kg of fuel, and consists of a
2.3 meter long, 2 meter wide spacecraft deck with two fixed solar panel wings with a
total span of 7.9 meters and a sample return capsule mounted on top of
the deck. The spacecraft is spin stabilized at one revolution every 37.5
seconds. Propulsion is provided by a hydrazine monopropellant thruster
using a helium pressurant. Communication is S-band via a fixed antenna.
The solar panels provide a maximum of 254 Watts power to a nickle-hydrogen storage battery. Temperatures
are maintained by heaters and passive thermal control. The spacecraft is also
equipped with ion and electron electrostatic monitors to determine which
solar wind regime is being encountered and to help set the appropriate
collector voltage. Spacecraft subsystems and monitors are mounted
beneath the sample return capsule.

Sample Return Capsule

The sample return capsule is disc-shaped with a blunt conical top and bottom, 1.5 meters
in diameter and 1.31 meters high, with a total mass of about 225 kg.
It contains a 97.3 cm diameter science cannister which holds a
concentrator and three collector arrays. The collector arrays are flat
discs made of ultra-pure silicon, silicon carbide, germanium, sapphire, chemically deposited diamond, gold, aluminum, and metallic glass wafers which are exposed to the solar
wind. Isotopes of helium, oxygen, nitrogen, neon, radon, and other elements are implanted in the top 100 nm of these materials. The concentrator is an electrostatic
mirror which concentrates elements up to neon by a factor of
approximately 20. Each collector array is to be deployed for a different solar wind regime.

Mission Profile

Genesis launched successfully at 16:13:40.324 UT on 8 August 2001 on a Delta 7326 (a Delta II Lite launch vehicle with three strap-on solid-rocket boosters and a Star 37FM third stage). Approximately 1 hour later the spacecraft left low Earth orbit on a three month journey out towards the L1 Lagrangian Sun-Earth libration point, 0.01 AU from Earth, to be inserted into a halo orbit about the L1 point. The L1 point is beyond the influences of the geomagnetic field and its trapped particles. Genesis reached the L1 point on 16 November 2001 and fired its hydrazine thrusters for 268 seconds to insert itself into the halo orbit at 19:03 UT (2:03 p.m. EST). On 3 December 2001 it opened its collector arrays and began gathering samples of solar wind particles. It completed 5 halo orbits over 30 months collecting samples. In April of 2004 it ended sample collection and shut the door to the sample collection cannister.

The samples were stowed and sealed in the contamination-tight canister within the Sample Return Capsule and returned to Earth over a five month period, flying past the Earth and then returning in order to be positioned for daylight entry. On 8 September 2004 the sample return capsule was released from the main spacecraft bus at about 12:00 UT and re-entered the Earth's atmosphere at 15:52:47 UT (11:53 a.m. EDT, 9:53 a.m. local MDT) and should have deployed a drogue parachute 2 minutes 7 seconds after entry at 33 km altitude. The parachute never deployed and the capsule crashed in the desert at a speed of 311 km/hr, severely damaging the capsule. The science cannister was removed to a clean room and the sample collection fragments are now ready to be shipped to Johnson Space Center. The cause of the parachute failure is believed to be incorrectly installed accelerometers which were to deploy the parachutes. The science team is confident that most of the planned science can be recovered from the salvaged sample collectors.

The spacecraft bus looped around Earth after the capsule was released and headed back out towards the L1 point.

The original plan for re-entry was as follows: Six minutes after drogue chute deployment the main parafoil was to deploy at an altitude of 6 km over the U.S.A.F. Utah Test and Training Range, where it would be aerocaptured by one of two specially equipped helicopters at an altitude of about 2.5 km. The spacecraft had the capability of going into a parking orbit if the weather at the capture site was unsuitable. The capsule was taken to a clean room at the U.S. Army Dugway Proving Ground and will be transported to Johnson Space Center for contamination control and curation, and distributed to selected Advanced Analytical Instrument Facilities for analysis.

There was some concern that the sample return capsule battery would fail, jeopardizing the re-entry. The battery was overheating in space, but ground tests showed that the battery should have been unaffected by the amount of heating it had endured, and should have operated to deploy the parachute on reentry. The actual cause of the parachute deployment failure is not known at this time.

Genesis was the fifth launch in NASA's Discovery program. The total cost of the project is $164 million for spacecraft development and science instruments and $45 million for operations and science data analysis.